1. Field of the Invention
This invention relates to a workpiece transfer device, more particularly to a workpiece transfer device for a forging machine.
2. Description of the Related Art
Referring to FIG. 1, a conventional forging machine 10 is shown to include a workpiece feeding mechanism 101 disposed on a machine frame 19 (see FIG. 3), and a cutting mechanism 102 disposed in front of the feeding mechanism 101. When an elongated blank 103 is straightened and fed to the cutting mechanism 102 by means of the feeding mechanism 101, the cutting mechanism 102 cuts the blank 103 to form a blank section 1040 of a predetermined length. Then the blank section 1040 is sent to a forging die mechanism 106 by a transfer mechanism 105. The forging die mechanism 106 includes fixed tubular die members 107 and punch-moved die members 108. The die members 108 are driven by a power source (not shown) to reciprocate relative to the die members 107. In the forging die mechanism 106, the blank section 1040, as shown in FIG. 2A, is clamped and is moved by the transfer mechanism 105 to the punch-moved die member 108. The blank section 1040 projects from the tubular die member 107 and is forged by means of the punch-moved die member 108 to form a first semi-finished product 1041, as best illustrated in FIG. 2B. The first semi-finished product 1041 is then transferred to the subsequent die member 107 by the transfer mechanism 105 and is further forged by means of the die members 107, 108 to form a second semi-finished product 1042, as best illustrated in FIG. 2C. The second semi-finished product 1042 is further moved by means of the transfer mechanism 105 and is further dealt with by means of the die members 107, 108 to form a final product 1043, as best illustrated in FIG. 2D. To remove a workpiece, such as products 1041, 1042 and 1043, from the corresponding die members 107, a workpiece ejecting mechanism 109 is disposed rearwardly of the die members 107 to push the workpiece out from the die members 107.
Referring to FIGS. 3 and 4, the transfer mechanism 105 has an elongated support member 11 and an elongated swing member 12 mounted on the machine frame 19. The end portions of the support member 11 and the swing member 12 are connected pivotally to one another by means of two connecting members 13 to form a parallelogram linkage system. When the swing member 12 is reciprocated in the directions as indicated by a double-headed arrow 18 by a power source (not shown), the support member 11 is reciprocated in the directions as indicated by the arrow 18. The other components of the transfer mechanism 105 are connected operatively to the machine frame 19, the support member 11 and the swing member 12. The machine frame 19 may have a plurality of transfer mechanisms 105 (only one transfer mechanism 105 is shown in detail in the drawings) provided thereon in order to increase the processing capacity of the forging machine 10. Each of the transfer mechanisms 105 includes an actuating mechanism 14, a push mechanism 15, a lever mechanism 16, and a workpiece holding mechanism 17. The actuating mechanism 14 has a power-driven cam member 141 and a cam-actuated rocker arm 142. The cam-actuated rocker arm 142 has an input end 143 and an output end 144. The input end 143 is actuated by the cam member 141 to move upwardly and downwardly the output end 144. The push mechanism 15 has a pneumatically operated piston 151 disposed under the output end 144. The lever mechanism 16 has a transmission rocker arm 161 connected pivotally to a stationary part 11 of the forging machine 10 The transmission rocker arm 161 has an input end 162 and an output end 163. The input end 162 of the transmission rocker arm 161 is disposed between the output end 144 of the cam-actuated rocker arm 142 and the piston 151. The workpiece holding mechanism 17 is fixed in front of the swing member 12 and has a vertical shaft 171 journalled in the swing member 12. The vertical shaft 171 has an upper end portion that is connected pivotally to the output end 163 of the transmission rocker arm 161, and a lower end portion that is connected perpendicularly to a horizontal shaft 172. The horizontal shaft 172 has a cross pair of clamping members 173 connected pivotally to one another at a front end thereof. Each of the clamping members 173 has a pair of clamping arms 174 coupled to a lower end thereof. In operation, the cam member 141 is actuated to rotate. Before the cam member 141 cams the input end 143 of the cam-actuated rocker arm 142, the piston 151 pushes upwardly the input end 162 and the output end 144, thereby resulting in downward movement of the output end 163. The vertical shaft 171 in the swing member 12 then descends to move the clamping members 173 toward one another via the horizontal shaft 172. As such, the blank sections 1040, 1041, 1042, and 1043 can be clamped by the clamping members 173, as best illustrated in FIGS. 2A to 2D. On the other hand, when the cam member 141 is rotated to actuate the cam-actuated rocker arm 142, the vertical shaft 171 can be lifted upwardly to move the clamping members 173 away from one another in order to release the blank sections 1040, 1041, 1042, and 1043. During the clamping and releasing operations of the clamping members 173, the swing member 12 reciprocates by action of the power source along the direction indicated by the arrow 18 in order to deliver blank sections 1040, 1041, 1042, and 1043 among the forging die mechanisms 106.
The conventional transfer mechanism 105 suffers from the following disadvantages:
1. With reference to FIG. 3, since the swing member 12 is relatively long and is suspended on the front side of the machine frame 19 by means of the connecting members at two ends thereof, the swing member 12 has an insufficient rigidity and is liable to flex or deform. Therefore, when a vertical force is exerted on the swing member 12 via the output end 163 of the transmission rocker arm 161, the swing member 12 will vibrate during the reciprocating movement of the swing member 12. The vibration of the swing member 12 results in shaking or wobbling of the blank sections 1040, 1041, 1042, 1043, thereby affecting adversely the subsequent die-punching process for the blank sections 1040, 1041, 1042, 1043.
2. With reference to FIG. 1, since the distance among the die members 107 or 108 is set to be small in order to minimize the stroke of the swing member 12, the spaces among the push mechanisms 15 are limited. As such, the size of an air cylinder or spring that is disposed under the input end 162 and the output end 144 and that is adapted to reciprocate the piston 151 is limited. Therefore, the force exerted on the input end 162 by the piston 151 is limited, thereby limiting the clamping force of the clamping members 173 and reducing the manufacturing speed and yield.
3. Each pair of clamping members 173 on each of the workpiece holding mechanisms 17 moves away from one another by an opening angle to release a corresponding one of the blank sections 1040, 1041, 1042, and 1043 before a corresponding one of the punch-moved die members 108 punches the corresponding one of the blank sections 1040, 1041, 1042, and 1043. However, since the opening angle of each pair of the clamping members 173 is relatively small, the clamping members 173 cannot move across the die member 108 to an adjacent die member 107 in order to clamp another blank section that is ejected out from the die member 107 by a corresponding one of the workpiece ejecting mechanisms 109 unless the die member 109 moves away from the die member 107. As such, the time required for manipulating the transfer mechanisms 105 is relatively long.
The object of the present invention is to provide a transfer mechanism for a forging machine that has an improved structural strength and that can hold blank sections in a more stable manner.
Another object of the present invention is to provide a transfer mechanism for a forging machine that can be manipulated in a time-efficient manner.
According to the present invention, a workpiece transfer device comprises an elongated hollow housing, a plurality of actuating mechanisms, a plurality of push mechanisms, a plurality of coupling devices, a plurality of levex mechanisms, and an elongated swing member.
Each of the actuating mechanisms has a cam member, and an actuating rocker arm operatively connected to the cam member. The actuating rocker arm of each of the actuating mechanisms has an output end that extends over a top side of the housing and that is movable toward and away from the top side of the housing when the cam member is actuated.
The push mechanisms have a plurality of spindles disposed inside and spaced longitudinally of the housing and movable vertically relative to the top side of the housing, and a plurality of biasing units for urging the spindles to move upwardly Each of the spindles has an upper end extending through the top side of the housing to abut against the output end of the actuating rocker arm of a corresponding one of the actuating mechanisms by biasing action of a corresponding one of the biasing units. Each of the spindles is movable downwardly against the biasing action of the corresponding one of the biasing units when the output end of the actuating rocker arm of the corresponding one of the actuating mechanisms moves downwardly.
Each of the coupling devices has a cylindrical sleeve member sleeved rotatably on a corresponding one of the spindles, and at least one cantilever extending radially from the sleeve member for turning about the corresponding one of the spindles. The cantilever of each of the coupling devices has a distal end distal from the corresponding one of the spindles.
Each of the lever mechanisms has a lever connected pivotally to the cantilever of a corresponding one of the coupling devices. The lever of each of the lever mechanisms has a first end portion engaging the corresponding one of the spindles to move upwardly and downwardly therewith, and a second end portion adjacent to the distal end of the cantilever of the corresponding one of the coupling devices.
The elongated swing member is connected pivotally to the distal end of the cantilever of each of the coupling devices to swing in a swing direction that is parallel to a length of the housing. The swing member has a plurality of primary vertical shafts extending therethrough and spaced longitudinally thereof. Each of the primary vertical shafts has an upper end that is connected universally to the second end portion of the lever of a corresponding one of the lever mechanisms in order to move upwardly and downwardly together with the second end portion of the lever of the corresponding one of the lever mechanisms.
As disclosed herein, the workpiece transfer device further comprises a plurality of workpiece holding devices connected operatively to the primary vertical shafts for clamping and releasing workpieces when the primary vertical shafts are moved upwardly and downwardly by the lever mechanisms. Each of the biasing units has an air cylinder disposed outside the housing, a piston member disposed in the air cylinder, and a push rocker arm. The push rocker arm of each of the biasing units has opposite first and second ends that abut respectively against the piston member and a lower end of the corresponding one of the spindles.
In a preferred embodiment, the swing member includes an elongated hollow casing of a generally rectangular cross section and having a top wall, a front wall connected perpendicularly to the top wall, and a plurality of pillars extending upwardly from the top wall. Each of the pillars has an axial through hole extending into an interior of the casing. The axial through hole of each of the pillars has a corresponding one of the primary vertical shafts journalled therein. The distal end of each of the cantilevers is connected perpendicularly and pivotally to a corresponding one of the pillars. Each of the workpiece holding devices has a pair of horizontal shafts extending perpendicularly through and journalled in the front wall of the casing. The horizontal shafts have inner ends disposed inside the casing, and outer ends disposed outside the casing. Each of the workpiece holding devices further has two gear members fixed respectively adjacent to the inner ends of the horizontal shafts and meshing with one another, two cross members connected respectively and perpendicularly to the outer ends of the horizontal shafts, and two clamping arms connected respectively to the cross members. Each of the primary vertical shafts has a lower end connected to one of the gear members on the horizontal shafts of a corresponding one of the workpiece holding devices in order to turn the gear members relative to one another, thereby turning the clamping arms to move toward and away from one another via the horizontal shafts and the cross members. A linking plate is connected pivotally to the pillars of the swing member and is elongated in a direction parallel to the swing direction.
In an alternate preferred embodiment, the swing member has an elongated base of a generally rectangular cross section and having a top face, a front face connected perpendicularly to the top face, and a plurality of hollow pillars extending upwardly from the top face. Each of the pillars is connected perpendicularly and pivotally to the distal end of a corresponding one of the cantilevers. Each of the primary vertical shafts extends into and is journalled in a corresponding one of the pillars.
Each of the primary vertical shafts has a lower end and a longitudinal rack portion formed adjacent to the lower end thereof. Each of the pillars has an opening facing the housing, a hollow block sleeved thereon and having an inner space communicated with the opening, a pinion disposed in the inner space and having teeth that extend into each of the pillars through the opening and that engage the longitudinal rack portion of a corresponding one of the primary vertical shafts, two connecting shafts extending oppositely from the pinion through the hollow block and extending transversely of a corresponding one of the pillars, and two crank arms connected perpendicularly and respectively to distal ends of the connecting shafts and extending forwardly to the front face of the base on opposite sides of the hollow block.
The front face of the base has a plurality of horizontal shafts extending forwardly therefrom and staggered vertically with respect to vertical lines passing through the pillars. Each of the workpiece holding devices has a secondary vertical shaft disposed in front of the front face of the base of the swing member and a corresponding one of the pillars, and connected pivotally to distal ends of the crank arms in order to move upwardly and downwardly when the primary vertical shafts are moved upwardly and downwardly. Each of the workpiece holding devices further has two link rods having upper ends connected pivotally to a lower end of the secondary vertical shaft and lower ends, two cross members having intermediate portions connected pivotally and respectively to the lower ends of the link rods, two swing ends, and two pivot ends that are connected pivotally to two adjacent ones of the horizontal shafts, and two clamping arms connected respectively to the swing ends.